DEFECT CHEMISTRY AND LUMINESCENCE OF ZNS - CU, AU, AL

Present high quality CRT TV sets employ wurtzite-(Zn,Cd)S:Cu,Al phosphor or its Cd-free variant sphalerite-ZnS:Cu,Au,Al to generate the green primary colour. If prepared properly, both phosphors exhibit the desired emission properties. However, the Au-codoped material tends to large variations of the emission as a function of the preparation procedure and thus is more demanding in terms of precise control of the manufacturing process. - This work aims at a better understanding of these peculiarities. Experiments are presented which demonstrate the large influence of the defect chemistry of the ZnS-host on the Au-related emission, whereas the Cu-related emission is affected to a lesser extent. - Possible techniques for a fine-tuning of the emission spectrum are discussed and evaluated according to the requirements of screen manufacture.